What are the losses in a pump ?

The losses in the pump can be categorized into three categories

Mechanical Losses
The first type of losses is the mechanical loss.  This loss is due to friction between the pump components such as the impeller and the bearings.

Hydraulic Losses
These losses occur due to the energy expended in overcoming the friction between the fluid and the impeller surface

Volumetric Losses
Volumetric Losses occur due to re-circulation of the fluid within the pump.  This does not contribute towards the development of pressure.

Leakage Losses
Leakage Loss is caused due to leakage of the liquid from the pump due to reasons such as malfunctioning of seals, etc.